The system block diagram of a conventional remote-controlled game motor or plane is shown in FIG. 1, in which the remote-controlled signal transmitter 2 accepts manual instructions from the joystick 1, and transmits signals to the receiver 3 of a game motor or plane. After being processed the signals will be inputted to a digital servo motor controller 4 for controlling the motor 5 of the game motor or plane, so as to rotate the wheels of the motor or control the propplers of the plane.
The circuits between the digital servo motor controller 4 and the motor 5 are shown in FIG. 2. The digital servo motor controller 4 has two outputs OUT1 and OUT2, after being passed through the INV1 and INV2 respectively to generate OUT1B and OUT2B, four signals OUT1, OUT2, OUT1B, OUT2B will be inputted to power MOS transistors PMOS1, NMOS2, PMOS3, NMOS4 respectively. Four diodes D1, D2, D3, D4 are parallel connected with the four power MOS transistors PMOS1, NMOS2, PMOS3, NMOS4 respectively as shown. Since the breakdown voltage of the four diodes is lower than that of the four power MOS transistors, the four power MOS transistors will be prevented from damaging by any static voltage. PMOS1 and NMOS2 are serially connected at point A. PMOS3 and NMOS4 are serially connected at point B. The motor 5 is connected between point A and B.
When OUT1 and OUT2 are both “0”, the motor 5 is stopped. When OUT1 is “0”, OUT2 is “1”, the motor 5 will be turned left. When OUT1 is “1”, OUT2 is “0”, the motor 5 will be turned right. OUT1 and OUT2 are both “1” is prohibited. Table 1 shows the results.
TABLE 1OUT1OUT2motor 500stop01turn left10turn right11prohibited
Table 1 shows the operation of the system. When the system is not operated, the digital servo motor controller 4 and the motor 5 are not powered on, and the motor 5 can be rotated manually to adjust the initial position. As the motor 5 is rotated manually, the motor 5 will become a generator to generate some power to be fed back to digital servo motor controller 4 and cause both OUT1 and OUT2 to be “1”, so as to short the points A and B of the motor 5. Due to this short situation, a huge amount of reverse current will be generated and fed to the motor 5, and generate a great reverse torque to resist the manual rotating of the motor, therefore the initial position of the motor 5 is not very easy to be adjusted.